sukhmander singh - Professor and Chairman, Civil Engineering Dept.- Santa Clara University, Santa Clara, CA

The paper presents a summary of the results of cyclic triaxial load testing of samples of silt, and silty sands. The paper emphasizes differences in behavior observed between reconstituted triaxial samples of clean sand, of sand containing ۱۰, ۲۰, ۳۰ and ۶۰ percent silt, pure silt, and undisturbed samples of silt and silty sand. An important observation is that the mechanisms of deformation for silt are different for reconstituted and undisturbed samples, the undisturbed sample having a specific " ic" structure which seems to slow down the excess pore water pressure accumulation, but which still results in cyclic deformations regularly increasing from the very beginning of the test and rapidly reaching high levels. The other important observation is that fine grained non-cohesive soils such as silts and silty sands can be as or even more susceptible to liquefaction as clean sands. Test results on samples of sands containing ۱۰, ۲۰ or ۳۰ percent of silt indicate lesser resistance to liquefaction than that of pure sand samples. The paper shows the difficulty in identifying a representative parameter to compare the behavior of silts and silty sands with pure sand, and it seems that more research will be needed in this area,